Wafer carrying apparatus

ABSTRACT

A wafer carrying apparatus disposed in a dry etching chamber is provided. The wafer carrying apparatus comprises at least an insulation plate, a conductive element and an insulation ring. The insulation plate has a cavity and a protruding portion surrounding the cavity. The conductive element is disposed in the cavity. The insulation ring covers at least the exposed top surface of the protruding portion.

BACKGROUND OF THE INVENTION

1. Field of Invention

The present invention relates to a fabrication apparatus used in semiconductor manufacturing processes. More particularly, the present invention relates to a wafer carrying apparatus used in a dry etching chamber.

2. Description of Related Art

In the semiconductor manufacturing process, to clear the silicon oxide or metal oxide on the semiconductor wafer in order to reduce the contact resistance and improve the flatness of the wafer surface, argon gas is usually used as the gas source of the plasma etching chamber for a dry etching process.

The conventional wafer carrying apparatus disposed in the plasma etching chamber is composed of an insulation plate and an iron plate. The iron plate is embedded in the insulation plate and the wafer is disposed on the iron plate and covers the interface of the iron plate and the insulation plate.

In the plasma etching process, the ion bombardment is usually performed in a direction perpendicular to the wafer surface and the ions are injected uniformly into the wafer. However, the bigger ions with greater density may be attracted to the edge of the wafer in a non-right angle. For the insulation plate below the wafer, the ion bombardment may readily cause damages to the insulation plate and generate a lot of undesirable particles. The damages of the insulation plate may shorten the use life of the insulation plate and thus increase the production costs. In addition, those undesirable particles may also result in contamination of the wafer, thus reducing the yield of the manufacturing process.

Moreover, in order to prevent those particles from contaminating the wafer, a periodic maintenance must be preformed for the dry etching chamber after every 2000 wafers are etched. Hence, not only the up time of the machine is reduced, but also the fabrication time of the whole process is prolonged.

SUMMARY OF THE INVENTION

Accordingly, the present invention is directed to provide a wafer carrying apparatus, which can substantially lower the frequency of the periodic maintenances, and improve the up time of the machine. Hence, the fabrication cost is reduced and the yield is improved.

The present invention provides a wafer carrying apparatus used in a dry etching chamber, for carrying a wafer. The wafer carrying apparatus comprises at least an insulation plate, a conductive element and an insulation ring. The insulation plate has a cavity and a protruding portion surrounding the cavity. The conductive element is disposed in the cavity. The insulation ring covers at least the exposed top surface of the protruding portion.

According to the embodiment of the present invention, the top surface of the insulation ring in the wafer carrying apparatus is a flat surface. The wafer is disposed on the insulation ring, and the inner diameter of the insulation ring is not greater than the diameter of the wafer. The insulation ring surrounds the conductive element.

In the wafer carrying apparatus according to the embodiment of the present invention, the top surface of the conductive element is higher than the top of the insulation plate, and the top surface of the conductive element is not higher than the top surface of the insulation ring.

In the wafer carrying apparatus according to the embodiment of the present invention, the material of the insulation ring and the insulation plate includes, for example, ceramic.

In the wafer carrying apparatus according to the embodiment of the present invention, the material of the conductive element is, for example, titanium. The conductive element comprises a pedestal and a shield above the pedestal. The material of the pedestal is, for example, titanium, and the material of the shield is, for example, stainless steel.

The present invention adopts the insulation ring to cover the insulation plate, so as to prevent the ion bombardment from damaging the insulation plate. Not only the generation of undesirable particles can be reduced and the use life of the insulation plate can be prolonged, but also the frequency of the periodic maintenance can be reduced substantially, and the up time of the machine can be improved. Furthermore, the fabricating cost can be reduced and the production efficiency can be improved.

In order to the make the aforementioned and other objects, features and advantages of the present invention comprehensible, a preferred embodiment accompanied with figures is described in detail below.

It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.

FIG. 1 is a schematic cross-sectional diagram of a dry etching chamber.

FIG. 2 shows a schematic cross-sectional diagram and a schematic top view of a wafer carrying apparatus according to one embodiment of the present invention.

DESCRIPTION OF EMBODIMENTS

FIG. 1 is a schematic cross-sectional diagram of a dry etching chamber, in which a wafer carrying apparatus according to one embodiment of the present invention is disposed. FIG. 2 shows a schematic cross-sectional diagram and a schematic top view of a wafer carrying apparatus according to one embodiment of the present invention.

Referring to FIG. 1, the wafer carrying apparatus 110 is disposed in a dry etching chamber 150 to carry a wafer 100. The wafer carrying apparatus 110 includes an insulation plate 120, a conductive element 30 and an insulation ring 140. The insulation plate 120 has a cavity 123 and a protruding portion 125 surrounding the cavity 123. The conductive element 130 is disposed in the cavity 123. The insulation ring 140 covers at least the exposed top surface of the protruding portion 125.

The material of the insulation plate 120 can be, for example, quartz, ceramic, sapphire, boron nitride, or graphite. The width of the cavity 123 of the insulation plate 120 is equal to or slightly larger than the width of the conductive element 130, so that the conductive element 130 can be chucked in the cavity 123. The conductive element 130 comprises a pedestal 133 and a shield 135 on the pedestal 133. The material of the pedestal 133 is, for example, a metal, and the preferred material is titanium, and, the material of the shield 135 is, for example, a metal, such as stainless steel.

The top surface of the insulation ring 140 is a flat surface, which covers the exposed top surface of the protruding portion 125, so that the external corner of the protruding portion 125 can be protected by the insulation ring 140. The material of the insulation ring 140 can be, for example, quartz, ceramic, sapphire, boron nitride, or graphite, and the preferred material is ceramic for the uniform flat surface. In one embodiment, the insulation ring 140 covers the protruding portion 125 of the insulation plate 120, and protrudes outward from the protruding portion 125.

Referring to FIG. 2, the inner diameter of the insulation ring 140 is, for example, less than the diameter of the wafer 100, and the inner diameter of the insulation ring 140 is, for example, equal to the diameter of the conductive element 130. From the top view part of FIG. 2, the size of the wafer 100 is greater than that of the conductive element 130 and less than that of the insulation ring 140. The top surface of the conductive element 130 is, for example, slightly higher than the top surface of the insulation plate 120. The top surface of the conductive element 130 can be leveled with the top surface of the insulation ring 140, and the wafer 100 is disposed on the top surfaces of the conductive element 130 and the insulation ring 140 (as shown in FIG. 2). Alternatively, the top surface of the insulation ring 140 may be slightly higher than the top surface of the conductive element 130, so that the wafer 100 is disposed on the top surface of the insulation ring 140. In one embodiment, in order to match the thickness of the applied conductive element 130, the thickness of the insulation plate 120 may thinner than the thickness of the conventional insulation plate. Therefore, the insulation ring 140 is able to be disposed on the insulation plate 120 and chucked with the conductive element 130 so as to fix the position of the insulation ring 140 indirectly.

Referring to FIG. 1, when a dry etching process is performed, first, the gas is introduced into the dry etching chamber 150, and a bias voltage is applied to the coil 155 above the dry etching chamber 150 to dissociate the gas into positive charged ions and electrons. The lower part of the dry etching chamber 150 is electrically connected with the injection frequency power 160. First, the electrons are attracted to be congregated on the top surface of the wafer 100, and the ions 170 bombard downward to the top surface of the wafer 100 through the attraction of the electrons. The dry etching process can be used to define the patterns during the fabricating processes, or used in the pre-clean process for cleaning the oxides on the wafer 100.

It is remarkable that, as the insulation plate 120 of the present invention is covered by the insulation ring 140 and the insulation ring 140 protrudes from the insulation plate 120, the ions 170 bombard on the flat surface (the top surface) of the insulation ring 140, rather than to the curved corners of the insulation plate 120. Compared with the conventional design, the bonds of the flat surface are not easily broken, and the possibility of the particle generation can be reduced substantially. The wafer 100 can be protected from being contaminated, and the production yield is increased. Further, the insulation plate 120 is protected from being damaged, so that the use life of the insulation plate is prolonged and the production cost is reduced. As a result, the maintenance frequency of the machine is lowered and the up time of the machine is improved.

It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. 

1. A wafer carrying apparatus, disposed in a dry etching chamber to carry a wafer, wherein the wafer carrying apparatus at least comprises: an insulation plate, having a cavity and a protruding portion surrounding the cavity; a conductive element, disposed in the cavity; and an insulation ring, covering at least a top surface of the protruding portion.
 2. The wafer carrying apparatus as claimed in claim 1, wherein a surface of the insulation ring is a flat surface.
 3. The wafer carrying apparatus as claimed in claim 1, wherein the wafer is disposed on the insulation ring, and an inner diameter of the insulation ring is not greater than a diameter of the wafer.
 4. The wafer carrying apparatus as claimed in claim 1, wherein a top surface of the conductive element is higher than a top of the insulation plate, and the top surface of the conductive element is not higher than a top surface of the insulation ring.
 5. The wafer carrying apparatus as claimed in claim 1, wherein the insulation ring surrounds the conductive element.
 6. The wafer carrying apparatus as claimed in claim 1, wherein a material of the insulation ring and the insulation plate includes ceramic.
 7. The wafer carrying apparatus as claimed in claim 1, wherein a material of the conductive element includes titanium.
 8. The wafer carrying apparatus as claimed in claim 1, wherein the conductive element comprises a pedestal and a shield above the pedestal.
 9. The wafer carrying apparatus as claimed in claim 8, wherein a material of the pedestal includes titanium.
 10. The wafer carrying apparatus as claimed in claim 8, wherein a material of the shield includes stainless steel.
 11. The wafer carrying apparatus as claimed in claim 1, wherein a material of the insulation plate includes ceramic. 